{"id":803,"date":"2025-01-17T11:02:54","date_gmt":"2025-01-17T03:02:54","guid":{"rendered":"https:\/\/eve2333.top\/?p=803"},"modified":"2025-01-17T11:02:55","modified_gmt":"2025-01-17T03:02:55","slug":"mysql%e6%95%b0%e6%8d%ae%e5%ba%93%e5%85%a5%e9%97%a8%e5%88%b0%e5%a4%a7%e8%9b%87%e5%b0%9a%e7%a1%85%e8%b0%b7%e5%ae%8b%e7%ba%a2%e5%ba%b7%e8%80%81%e5%b8%88%e7%ac%94%e8%ae%b0-%e5%9f%ba%e7%a1%80%e7%af%87-pa-2","status":"publish","type":"post","link":"https:\/\/eve2333.top\/?p=803","title":{"rendered":"MySQL\u6570\u636e\u5e93\u5165\u95e8\u5230\u5927\u86c7\u5c1a\u7845\u8c37\u5b8b\u7ea2\u5eb7\u8001\u5e08\u7b14\u8bb0 \u57fa\u7840\u7bc7 part 5"},"content":{"rendered":"\n

\u7b2c05\u7ae0_\u6392\u5e8f\u4e0e\u5206\u9875<\/h1>\n\n\n\n

\u6392\u5e8f<\/h3>\n\n\n\n
#\u7b2c05\u7ae0_\u6392\u5e8f\u4e0e\u5206\u9875\n\n#1. \u6392\u5e8f\n\n# \u5982\u679c\u6ca1\u6709\u4f7f\u7528\u6392\u5e8f\u64cd\u4f5c\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u67e5\u8be2\u8fd4\u56de\u7684\u6570\u636e\u662f\u6309\u7167\u6dfb\u52a0\u6570\u636e\u7684\u987a\u5e8f\u663e\u793a\u7684\u3002\nSELECT * FROM employees;\n<\/code><\/pre>\n\n\n\n
# 1.1 \u57fa\u672c\u4f7f\u7528\n# \u4f7f\u7528 ORDER BY \u5bf9\u67e5\u8be2\u5230\u7684\u6570\u636e\u8fdb\u884c\u6392\u5e8f\u64cd\u4f5c\u3002\n# \u5347\u5e8f\uff1aASC (ascend)\n# \u964d\u5e8f\uff1aDESC (descend)\n\n# \u7ec3\u4e60\uff1a\u6309\u7167salary\u4ece\u9ad8\u5230\u4f4e\u7684\u987a\u5e8f\u663e\u793a\u5458\u5de5\u4fe1\u606f\n#\u4f7f\u7528ORDERBY\u5bf9\u67e5\u8be2\u5230\u6570\u636e\u6392\u5e8f\u64cd\u4f5c\nSELECT employee_id,last_name,salary\nFROM employees\nORDER BY salary DESC;\n\n# \u7ec3\u4e60\uff1a\u6309\u7167salary\u4ece\u4f4e\u5230\u9ad8\u7684\u987a\u5e8f\u663e\u793a\u5458\u5de5\u4fe1\u606f\nSELECT employee_id,last_name,salary\nFROM employees\nORDER BY salary ASC;\n\n\nSELECT employee_id,last_name,salary\nFROM employees\nORDER BY salary; # \u5982\u679c\u5728ORDER BY \u540e\u6ca1\u6709\u663e\u5f0f\u6307\u540d\u6392\u5e8f\u7684\u65b9\u5f0f\u7684\u8bdd\uff0c\u5219\u9ed8\u8ba4\u6309\u7167\u5347\u5e8f\u6392\u5217\u3002<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u4f7f\u7528\u4e0d\u5728SELECT\u5217\u8868\u4e2d\u7684\u5217\u6392\u5e8f\u3002<\/p>\n\n\n\n
\u5728\u5bf9\u591a\u5217\u8fdb\u884c\u6392\u5e8f\u7684\u65f6\u5019\uff0c\u9996\u5148\u6392\u5e8f\u7684\u7b2c\u4e00\u5217\u5fc5\u987b\u6709\u76f8\u540c\u7684\u5217\u503c\uff0c\u624d\u4f1a\u5bf9\u7b2c\u4e8c\u5217\u8fdb\u884c\u6392\u5e8f\u3002\u5982\u679c\u7b2c \u4e00\u5217\u6570\u636e\u4e2d\u6240\u6709\u503c\u90fd\u662f\u552f\u4e00\u7684\uff0c\u5c06\u4e0d\u518d\u5bf9\u7b2c\u4e8c\u5217\u8fdb\u884c\u6392\u5e8f\u3002 <\/p>\n\n\n\n
#2. \u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u5217\u7684\u522b\u540d\uff0c\u8fdb\u884c\u6392\u5e8f\nSELECT employee_id,salary,salary * 12 annual_sal\nFROM employees\nORDER BY annual_sal;\n\n#\u5217\u7684\u522b\u540d\u53ea\u80fd\u5728 ORDER BY \u4e2d\u4f7f\u7528\uff0c\u4e0d\u80fd\u5728WHERE\u4e2d\u4f7f\u7528\u3002\n#\u5982\u4e0b\u64cd\u4f5c\u62a5\u9519\uff01\n#########ERROR######################\nSELECT employee_id,salary,salary * 12 annual_sal\nFROM employees\nWHERE annual_sal > 81600;\n###########ERROR###################\n\n#3. \u5f3a\u8c03\u683c\u5f0f\uff1aWHERE \u9700\u8981\u58f0\u660e\u5728FROM\u540e\uff0cORDER BY\u4e4b\u524d\u3002\nSELECT employee_id,salary\nFROM employees\nWHERE department_id IN (50,60,70)\nORDER BY department_id DESC;\n\n#4. \u4e8c\u7ea7\u6392\u5e8f\n\n#\u7ec3\u4e60\uff1a\u663e\u793a\u5458\u5de5\u4fe1\u606f\uff0c\u6309\u7167department_id\u7684\u964d\u5e8f\u6392\u5217\uff0csalary\u7684\u5347\u5e8f\u6392\u5217\nSELECT employee_id,salary,department_id\nFROM employees\nORDER BY department_id DESC,salary ASC;<\/code><\/pre>\n\n\n\n
 \u5206\u9875<\/h3>\n\n\n\n
\u80cc\u666f1\uff1a\u67e5\u8be2\u8fd4\u56de\u7684\u8bb0\u5f55\u592a\u591a\u4e86\uff0c\u67e5\u770b\u8d77\u6765\u5f88\u4e0d\u65b9\u4fbf\uff0c\u600e\u4e48\u6837\u80fd\u591f\u5b9e\u73b0\u5206\u9875\u67e5\u8be2\u5462\uff1f
\u80cc\u666f2\uff1a\u8868\u91cc\u6709 4 \u6761\u6570\u636e\uff0c\u6211\u4eec\u53ea\u60f3\u8981\u663e\u793a\u7b2c 2\u30013 \u6761\u6570\u636e\u600e\u4e48\u529e\u5462\uff1f<\/p>\n\n\n\n
#2. \u5206\u9875\n#2.1 mysql\u4f7f\u7528limit\u5b9e\u73b0\u6570\u636e\u7684\u5206\u9875\u663e\u793a\n\n# \u9700\u6c421\uff1a\u6bcf\u9875\u663e\u793a20\u6761\u8bb0\u5f55\uff0c\u6b64\u65f6\u663e\u793a\u7b2c1\u9875\nSELECT employee_id,last_name\nFROM employees\nLIMIT 0,20;\n\n\n# \u9700\u6c422\uff1a\u6bcf\u9875\u663e\u793a20\u6761\u8bb0\u5f55\uff0c\u6b64\u65f6\u663e\u793a\u7b2c2\u9875\nSELECT employee_id,last_name\nFROM employees\nLIMIT 20,20;\n\n\n# \u9700\u6c423\uff1a\u6bcf\u9875\u663e\u793a20\u6761\u8bb0\u5f55\uff0c\u6b64\u65f6\u663e\u793a\u7b2c3\u9875\nSELECT employee_id,last_name\nFROM employees\nLIMIT 40,20;\n\n#\u9700\u6c42\uff1a\u6bcf\u9875\u663e\u793apageSize\u6761\u8bb0\u5f55\uff0c\u6b64\u65f6\u663e\u793a\u7b2cpageNo\u9875\uff1a\n#\u516c\u5f0f\uff1aLIMIT (pageNo-1) * pageSize,pageSize;\n\n\n#2.2 WHERE ... ORDER BY ...LIMIT \u58f0\u660e\u987a\u5e8f\u5982\u4e0b\uff1a\n\n# LIMIT\u7684\u683c\u5f0f\uff1a \u4e25\u683c\u6765\u8bf4\uff1aLIMIT \u4f4d\u7f6e\u504f\u79fb\u91cf,\u6761\u76ee\u6570\n# \u7ed3\u6784\"LIMIT 0,\u6761\u76ee\u6570\" \u7b49\u4ef7\u4e8e \"LIMIT \u6761\u76ee\u6570\"\n\nSELECT employee_id,last_name,salary\nFROM employees\nWHERE salary > 6000\nORDER BY salary DESC\n#limit 0,10;\nLIMIT 10;\n\n#\u7ec3\u4e60\uff1a\u8868\u91cc\u6709107\u6761\u6570\u636e\uff0c\u6211\u4eec\u53ea\u60f3\u8981\u663e\u793a\u7b2c 32\u300133 \u6761\u6570\u636e\u600e\u4e48\u529e\u5462\uff1f\n\nSELECT employee_id,last_name\nFROM employees\nLIMIT 31,2;\n\n#2.3 MySQL8.0\u65b0\u7279\u6027\uff1aLIMIT ... OFFSET ...\n\n#\u7ec3\u4e60\uff1a\u8868\u91cc\u6709107\u6761\u6570\u636e\uff0c\u6211\u4eec\u53ea\u60f3\u8981\u663e\u793a\u7b2c 32\u300133 \u6761\u6570\u636e\u600e\u4e48\u529e\u5462\uff1f\n\nSELECT employee_id,last_name\nFROM employees\nLIMIT 2 OFFSET 31;\n\n#\u7ec3\u4e60\uff1a\u67e5\u8be2\u5458\u5de5\u8868\u4e2d\u5de5\u8d44\u6700\u9ad8\u7684\u5458\u5de5\u4fe1\u606f\nSELECT employee_id,last_name,salary\nFROM employees\nORDER BY salary DESC\n#limit 0,1\nLIMIT 1;\n\n#2.4 LIMIT \u53ef\u4ee5\u4f7f\u7528\u5728MySQL\u3001PGSQL\u3001MariaDB\u3001SQLite \u7b49\u6570\u636e\u5e93\u4e2d\u4f7f\u7528\uff0c\u8868\u793a\u5206\u9875\u3002\n# \u4e0d\u80fd\u4f7f\u7528\u5728SQL Server\u3001DB2\u3001Oracle\uff01<\/code><\/pre>\n\n\n\n
sql\u662f\u7ed3\u6784\u5316\u67e5\u8be2\u8bed\u8a00\uff0c\u800cmysql \u662fDBMS \u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\u4e5f\u5c31\u662f\u4e00\u4e2a\u8f6f\u4ef6\uff0c\u5c31\u50cfjava\u8bed\u8a00\u548cidea eclipse \u7b49\u7ee7\u627f\u5f00\u53d1\u73af\u5883\u4e00\u6837<\/p>\n\n\n\n
\n
\u5728\u4e0d\u540c\u7684 DBMS \u4e2d\u4f7f\u7528\u7684\u5173\u952e\u5b57\u53ef\u80fd\u4e0d\u540c\u3002\u5728 MySQL\u3001PostgreSQL\u3001MariaDB \u548c SQLite \u4e2d\u4f7f\u7528 LIMIT \u5173 \u952e\u5b57\uff0c\u800c\u4e14\u9700\u8981\u653e\u5230 SELECT \u8bed\u53e5\u7684\u6700\u540e\u9762\u3002<\/p>\n\n\n\n
\u5982\u679c\u662f SQL Server \u548c Access\uff0c\u9700\u8981\u4f7f\u7528 TOP \u5173\u952e\u5b57\uff0c\u6bd4\u5982\uff1a<\/p>\n\n\n\n
SELECT TOP 5 name, hp_max FROM heros ORDER BY hp_max DESC<\/code><\/pre>\n\n\n\n
\u5982\u679c\u662f DB2\uff0c\u4f7f\u7528 FETCH FIRST 5 ROWS ONLY \u8fd9\u6837\u7684\u5173\u952e\u5b57\uff1a<\/p>\n\n\n\n
SELECT name, hp_max FROM heros ORDER BY hp_max DESC FETCH FIRST 5 ROWS ONLY<\/code><\/pre>\n\n\n\n
\u5982\u679c\u662f Oracle\uff0c\u4f60\u9700\u8981\u57fa\u4e8e ROWNUM \u6765\u7edf\u8ba1\u884c\u6570\uff1a<\/p>\n\n\n\n
SELECT rownum,last_name,salary FROM employees WHERE rownum < 5 ORDER BY salary DESC;<\/code><\/pre>\n\n\n\n
\u9700\u8981\u8bf4\u660e\u7684\u662f\uff0c\u8fd9\u6761\u8bed\u53e5\u662f\u5148\u53d6\u51fa\u6765\u524d 5 \u6761\u6570\u636e\u884c\uff0c\u7136\u540e\u518d\u6309\u7167 hp_max \u4ece\u9ad8\u5230\u4f4e\u7684\u987a\u5e8f\u8fdb\u884c\u6392\u5e8f\u3002\u4f46 \u8fd9\u6837\u4ea7\u751f\u7684\u7ed3\u679c\u548c\u4e0a\u8ff0\u65b9\u6cd5\u7684\u5e76\u4e0d\u4e00\u6837\u3002\u6211\u4f1a\u5728\u540e\u9762\u8bb2\u5230\u5b50\u67e5\u8be2\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528<\/p>\n\n\n\n
SELECT rownum, last_name,salary \nFROM ( \n    SELECT last_name,salary \n    FROM employees \n    ORDER BY salary DESC) \nWHERE rownum < 10; <\/code><\/pre>\n\n\n\n
\u5f97\u5230\u4e0e\u4e0a\u8ff0\u65b9\u6cd5\u4e00\u81f4\u7684\u7ed3\u679c<\/p>\n<\/blockquote>\n\n\n\n
\u8bfe\u540e\u7ec3\u4e60<\/h3>\n\n\n\n
#1. \u67e5\u8be2\u5458\u5de5\u7684\u59d3\u540d\u548c\u90e8\u95e8\u53f7\u548c\u5e74\u85aa\uff0c\u6309\u5e74\u85aa\u964d\u5e8f \u6309\u59d3\u540d\u5347\u5e8f\u663e\u793a \nSELECT last_name,department_id,salary * 12 annual_salary\nFROM employees\nORDER BY annual_salary DESC,last_name ASC;\n\n# 2. \u9009\u62e9\u5de5\u8d44\u4e0d\u5728 8000 \u5230 17000 \u7684\u5458\u5de5\u7684\u59d3\u540d\u548c\u5de5\u8d44\uff0c\u6309\u5de5\u8d44\u964d\u5e8f\uff0c\u663e\u793a\u7b2c21\u523040\u4f4d\u7f6e\u7684\u6570\u636e\nSELECT last_name,salary\nFROM employees\nWHERE salary NOT BETWEEN 8000 AND 17000 \nORDER BY salary DESC\nLIMIT 20,20;\n\n# 3. \u67e5\u8be2\u90ae\u7bb1\u4e2d\u5305\u542b e \u7684\u5458\u5de5\u4fe1\u606f\uff0c\u5e76\u5148\u6309\u90ae\u7bb1\u7684\u5b57\u8282\u6570\u964d\u5e8f\uff0c\u518d\u6309\u90e8\u95e8\u53f7\u5347\u5e8f\nSELECT employee_id,last_name,email,department_id\nFROM employees\n#where email like '%e%'\nWHERE email REGEXP '[e]'\nORDER BY LENGTH(email) DESC,department_id ASC<\/code><\/pre>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\u7b2c05\u7ae0_\u6392\u5e8f\u4e0e\u5206\u9875 \u6392\u5e8f \u53ef\u4ee5\u4f7f\u7528\u4e0d\u5728SELECT\u5217\u8868\u4e2d\u7684\u5217\u6392\u5e8f\u3002 \u5728\u5bf9\u591a\u5217\u8fdb\u884c\u6392\u5e8f\u7684\u65f6\u5019\uff0c\u9996\u5148\u6392\u5e8f\u7684\u7b2c\u4e00\u5217\u5fc5\u987b\u6709\u76f8\u540c\u7684\u5217\u503c\uff0c\u624d …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-803","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=803"}],"version-history":[{"count":1,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/803\/revisions"}],"predecessor-version":[{"id":808,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/803\/revisions\/808"}],"wp:attachment":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=803"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}